Впервые пишу триггер, получаю ошибку

DROP TABLE IF EXISTS users; CREATE TABLE users ("name" TEXT);
DROP TABLE IF EXISTS logs; CREATE TABLE logs ( "text" text,  "added" TIMESTAMP WITHOUT TIME ZONE);
 
CREATE OR REPLACE FUNCTION add_to_log() RETURNS TRIGGER AS $$
DECLARE
    mstr VARCHAR(30);
    astr VARCHAR(100);
    retstr VARCHAR(254);
BEGIN
    IF  TG_OP = 'UPDATE' THEN
        astr = NEW.name;
        mstr := 'Update user ';
        retstr := mstr || astr;
        INSERT INTO logs(text,added) VALUES (retstr,NOW());
        RETURN NEW;
    ELSIF TG_OP = 'DELETE' THEN
        astr = OLD.name;
        mstr := 'Remove user ';
        retstr := mstr || astr;
        INSERT INTO logs(text,added) VALUES (retstr,NOW());
        RETURN OLD;
    END IF;
END;
$$ LANGUAGE plpgsql;
 
 
CREATE TRIGGER t_user
AFTER UPDATE OR DELETE ON users FOR EACH ROW EXECUTE PROCEDURE add_to_log();

CREATE OR REPLACE FUNCTION add_to_log() RETURNS TRIGGER AS $$

CREATE OR REPLACE FUNCTION add_to_log() RETURNS TRIGGER AS $Test$

CREATE TABLE employees(
   id SERIAL PRIMARY KEY,
   first_name VARCHAR(40) NOT NULL,
   last_name VARCHAR(40) NOT NULL
);

CREATE TABLE employee_audits (
   id SERIAL PRIMARY KEY,
   employee_id INT NOT NULL,
   last_name VARCHAR(40) NOT NULL,
   changed_on TIMESTAMP(6) NOT NULL
);

CREATE OR REPLACE FUNCTION log_last_name_changes()
  RETURNS TRIGGER AS
$BODY$
BEGIN
    IF NEW.last_name <> OLD.last_name THEN
         INSERT INTO employee_audits(employee_id,last_name,changed_on)
         VALUES(OLD.id,OLD.last_name,now());
    END IF;
 
    RETURN NEW;
END;
$BODY$;
 
CREATE TRIGGER last_name_changes
  BEFORE UPDATE
  ON employees
  FOR EACH ROW
  EXECUTE PROCEDURE log_last_name_changes();